code: def create_test_dataset(fn):
      with netCDF4.Dataset(fn, mode="w") as ds:
          ds.createDimension("x", 3)
          v = ds.createVariable("x", np.int32, ("x",))
          v[:] = np.arange(3)
  
          g = ds.createGroup("group")
          g2 = ds.createGroup("group/group1")
  
          v2 = ds.createVariable("group/y", np.int32, ("x",))
          v2[:] = np.arange(3) + 1
  
          v3 = ds.createVariable("group/group1/z", np.int32, ("x",))
          v3[:] = np.arange(3) + 2
  
file_path: distributed/distributed/protocol/tests/test_netcdf4.py
imports: from __future__ import annotations
  import pytest
  from dask.utils import tmpfile
  from distributed.protocol import deserialize, serialize
  import dask.array
  from distributed.utils_test import gen_cluster
label_desc: Use image node_id 1 for calling a global function with example usage: create_test_dataset(fn) without return types